How Climate Change Contributed to This Summer’s Wildfires

Firefighters discuss plans while battling the Carr Fire, in California. More than twelve thousand firefighters are working in California, and some have come from as far as Florida.Photograph by Noah Berger / AP

The image of the day from NASA’s Earth Observatory shows gusting plumes of smoke veiling the western United States. Two hundred thousand acres are on fire in California, fuelled by strong winds and unrelenting hot, dry conditions. The Carr Fire, in Redding, a hundred and sixty miles north of Sacramento, has incinerated over a thousand structures, most of them people’s homes. Forty thousand people have been evacuated, and six have died. The fire is so large—more than a hundred and ten thousand acres—that it has created its own weather system, making it difficult for firefighters to predict what it will do next.“We have seen extremely explosive fire behavior on this particular fire,” Chris Anthony, a division chief with the California Department of Forestry and Fire Protection, said. “But it’s not unique anymore to what we are seeing on fires in California.” Climate change is slow until it’s terrifyingly fast.

Farther south, in the Ferguson Fire, west of Yosemite Valley, two more people have died, a bulldozer operator and the captain of an élite firefighting squad. More than twelve thousand firefighters are working in California—some have come from as far as Florida—and on Saturday, President Trump declared a state of emergency in order to release federal funds. Ninety-five wildfires are scorching the country from Texas to Oregon, and have burned 4.8 million acres. “This is just July,” Lynne Tolmachoff, a spokeswoman for the California Department of Forestry and Fire Protection, told CBS. “So we’re not even into the worst part of fire season.”

Meanwhile, rains have swamped parts of the East Coast, and tornadoes have swept across the plains. More severe rainstorms and flash floods are expected in the South and the East Coast in the coming days. The jet stream—the freeway of air that circles the Northern Hemisphere—is behaving erratically, meandering like a drunk. “It’s one of these wavy jet-stream patterns that’s causing all the crazy weather,” Jennifer Francis, an atmospheric scientist at Rutgers, said. Francis and others have shown that this type of pattern is linked to the amplified warming in the Arctic. When the hot-to-cold temperature gradient from the mid-latitudes to the Arctic decreases, it can slow or split the jet stream, making it loopier, bringing persistent periods of extreme dry heat to some areas and heavy rainfall to others. In 2010, the Moscow heat wave and wildfires happened at the same time as monsoon rains and flooding in Pakistan. “We’re seeing the same thing this summer,” the Penn State climate scientist Michael Mann told me. “Those regional anomalies aren’t unrelated to each other—they are part of the same larger wave disturbance.”

Throughout the Northern Hemisphere this summer, heat waves have been shattering records and sustaining wildfires of unprecedented fury. In Greece last week, ninety-one people died in a hellish fire—Europe’s deadliest since 1900—that broke out eighteen miles east of Athens and, powered by unusually dry vegetation and strong winds, blazed across a resort town on the Aegean Sea. On July 17th, in Sodankylä, Finland, more than fifty miles north of the Arctic Circle, the thermometer read a previously unseen ninety degrees; in Sweden, wildfires swept across Lapland; in Norway, there have been three times more wildfires this summer than normal. In much of Germany, drought conditions have persisted since May, the Rhine is dangerously low, and authorities in the city of Potsdam, outside Berlin, were afraid last week that a wildfire burning around the nearby small town of Fichtenwalde would set off Second World War–era ammunition that remains buried in the area’s forest and meadows. In the United Kingdom, the first half of summer has been the driest on record.

The fast-moving Carr Fire has burned over forty-four thousand acres and destroyed dozens of homes.Photograph by Justin Sullivan / Getty

On Thursday, a group of international researchers concluded, in a preliminary report, that human-caused climate change doubled the odds of this summer’s European heat wave. (Because they based this conclusion only on temperature records, Mann told me that he believes it “vastly underestimates the impact that climate change had both on that specific heat wave, and, more generally, on all these specific weather events that we are seeing.”) Peter Gibson, a postdoctoral researcher at NASA’s Jet Propulsion Laboratory, has shown a link between the current clear, steep warming trend and the increased severity, frequency, and duration of regional heat waves. Last fall, he co-authored a study in Scientific Reports that was the first to analyze how disastrous such heat waves could become. “We found that parts of Europe and North America could experience an extra ten to fifteen heat-wave days per degree of global warming beyond what we have seen already,” he said recently.

Last week, in Kumagaya, Japan, the thermometer hit a hundred and six degrees—a new record. Japan’s two-week heat wave killed at least eighty people and hospitalized twenty-two thousand. This, after torrential floods earlier in the summer had left two hundred dead. On July 5th, the temperature reached a hundred and twenty-four degrees in Ouargla, Algeria, which is likely a record for Africa, and on June 26th, the day’s lowest temperature in the small fishing village of Quriyat, on the east coast of the Gulf of Oman, was a hundred and nine degrees. It was the hottest low temperature in the world’s recorded history.

This entire nightmare has been anticipated, in some detail, since the nineteen-eighties. June 23rd marked the thirtieth anniversary of Jim Hansen’s testimony before Congress that “the greenhouse effect has been detected and is changing our climate now.” As Elizabeth Kolbert wrote for the occasion, “It would be hard to think of a more lugubrious milestone.” Today’s extremes are proving not just consistent with those earlier warnings but, in some cases, worse. “We may be further along than we thought we might be at this point,” Mann said. There is still an endless amount to learn about connections between atmospheric phenomena, like how Arctic warming affects the jet stream. But new findings are unlikely to offer pleasant surprises. “The changes are much greater than what we predicted a decade ago,” Mann said. “Uncertainty is not our friend, despite what contrarians would like you to think.”